The Schedule F section of the 2020 turbo tax program has 2018 and 2019 for headings in the income section. is this an error or am I confused?

Try saving your return, exiting, then opening back up again. I just walked through this section briefly on my TurboTax Desktop and what I see pertains to 2020 so I am not sure where exactly you are seeing 2018 and 2019 unless you are looking at a comparative detail.

In some places the years have not been updated to reflect 2019 & 2020  ... eventually they will be corrected.  For now just  pretend they say 2019 & 2020  and not  2018 & 2019.  This doesn't affect how the program works, it is simply a typo.